Remove adapter code between MDCTypography and MDFRobotoFontLoader

ios/chrome/app/main_controller.mm

Index: ios/chrome/app/main_controller.mm
diff --git a/ios/chrome/app/main_controller.mm b/ios/chrome/app/main_controller.mm
index 5b0bda09a17730b19e62b5552f753b6068b4681e..21abdeef56ed988bf1e81a2f6d80e325408a3f99 100644
--- a/ios/chrome/app/main_controller.mm
+++ b/ios/chrome/app/main_controller.mm
@@ -135,6 +135,7 @@
 #import "ios/public/provider/chrome/browser/user_feedback/user_feedback_provider.h"
 #import "ios/third_party/material_components_ios/src/components/Typography/src/MaterialTypography.h"
 #import "ios/third_party/material_roboto_font_loader_ios/src/src/MaterialRobotoFontLoader.h"
+#import "ios/third_party/material_roboto_font_loader_ios/src/src/MDCTypographyAdditions/MDFRobotoFontLoader+MDCTypographyAdditions.h"
 #include "ios/web/net/request_tracker_factory_impl.h"
 #include "ios/web/net/request_tracker_impl.h"
 #include "ios/web/net/web_http_protocol_handler_delegate.h"
@@ -230,12 +231,6 @@ enum class StackViewDismissalMode { NONE, NORMAL, INCOGNITO };
 
 }  // namespace
 
-// TODO(crbug.com/673904): Remove once MDFRobotoFontLoader declares it directly.
-// MDFRobotoFontLoader implicitly implements MDCTypographyFontLoading but can't
-// declare it until MDC is public.
-@interface MDFRobotoFontLoader (MDCTypography)<MDCTypographyFontLoading>
-@end
-
 @interface MainController ()<BrowserStateStorageSwitching,
                              BrowsingDataRemovalControllerDelegate,
                              PrefObserverDelegate,